Sesh 2- Lipid metabolism Flashcards
What control is the storage of triacylglycerols under?
Hormonal (insulin promotes, glucagon inhibits)
What are the 2 possible fates of glycerol derived from dietary triacylglycerols?
Converted to glycerol phosphate in the liver for:
- TAG synthesis
- Glycolysis
Why are fatty acids ideal storage molecules?
They are hydrophobic and highly reduced.
Name the essential polyunsaturated fatty acid needed for prostaglandin synthesis.
Arachidonic acid.
Which enzyme catalyses lipolysis from adipose tissue?
Hormone-sensitive lipase.
How are fatty acids transported in the bloodstream?
Bound non-covalently to albumin.
Can red blood cells oxidise fatty acids?
No, as they don’t contain mitochondria.
Why does beta-oxidation of fatty acids not readily occur in the CNS?
Fatty acids cannot readily cross the blood-brain barrier.
Which molecule needs to be added to fatty acids to activate them prior to beta-oxidation?
Co-enzyme A
Where does fatty acid activation occur?
Outside the mitochondrion
How are activated fatty acids transported into the mitochondrial matrix?
Via a carnitine shuttle
Which intermediate of fatty acid oxidation inhibits the carnitine shuttled and why is this important?
- Malonyl Co A
- Prevents newly synthesised fatty acids in cytoplasm from immediately being oxidised in the mitochondria.
Briefly describe beta-oxidation of fatty acids.
- C2 units are sequentially removed from fatty acids until only 2 carbons remain.
- Requires FAD and NAD+
- C atoms from fatty acid are converted to acetyl CoA
Why can beta-oxidation not occur in the absence of oxygen?
Needs NAD+ and FAD which need to be re-oxidised in the electron transport chain, which relies on oxygen as the terminal electron acceptor.
Why can’t beta-oxidation occur in neutrophils?
They use their mitochondria for the respiratory burst.
